Fuel Lift Pump

Component Location:

The electric fuel lift pump mounts on the inside of the left frame rail, and is used to deliver fuel at a low pressure (at least 21 kPa or 3 psi) at the rate of 0.24 liter (1/2 pint) in 15 seconds (15 GPH). The lift pump is controlled by the PCM.

When the key is turned ON, the PCM energizes the fuel pump relay which sends a voltage to the lift pump. The lift pump remains on during the glow plug cycle. If the engine is not started immediately after the glow plug cycle, the PCM shuts the fuel lift pump OFF and waits until engine RPM is greater than zero and then turns the relay back ON. As a backup system to the fuel pump relay, the fuel lift pump can also be turned ON by the fuel pump/oil pressure switch. When the engine oil pressure reaches 28 kPa (4 psi), the fuel pump/oil pressure switch will close and complete the circuit to run the fuel lift pump.

The fuel manager/filter is an in-line type filter that combines several different functions by acting as a fuel filter, a water separator, a water detector, a water drain, and a fuel heater.

The fuel manager/filter mounts on the frame. The filter housing has an inlet fitting connecting to the pipe/hose from the lift pump and an outlet fitting connecting to the fuel injection pump with a hose.

The fuel manager/filter has a replaceable element. The element has an air vent valve on its top surface that is used during the lift pump diagnosis and the filter element replacement procedure. The fuel manager/filter also has a water-in-fuel sensor and a fuel heater.